ruby-on-rails - 使用 Ruby 从文本中删除硬换行符

Question

我有一些带有硬换行符的文本，如下所示:

This should all be on one line 
since it's one sentence.

This is a new paragraph that
should be separate.

我想删除单个换行符但保留双换行符，所以它看起来像这样:

This should all be on one line since it's one sentence.

This is a new paragraph that should be separate.

是否有一个正则表达式可以做到这一点？ (或一些简单的方法)

到目前为止，这是我唯一可行但感觉很老套的解决方案。

txt = txt.gsub(/(\r\n|\n|\r)/,'[[[NEWLINE]]]')
txt = txt.gsub('[[[NEWLINE]]][[[NEWLINE]]]', "\n\n")
txt = txt.gsub('[[[NEWLINE]]]', " ")

Answer 1

替换所有后面没有或前面没有换行符的换行符:

text = <<END
This should all be on one line
since it's one sentence.

This is a new paragraph that
should be separate.
END

p text.gsub /(?<!\n)\n(?!\n)/, ' '
#=> "This should all be on one line since it's one sentence.\n\nThis is a new paragraph that should be separate. "

或者，对于没有 lookarounds 的 Ruby 1.8:

txt.gsub! /([^\n])\n([^\n])/, '\1 \2'